How to use CSV values to drive object scale?
It seems I was confusing "Game Properties" in the Game Editor and "Custom Properties" in the Properties Editor.  By moving my Game Property to a Custom Property, I was able to manipulate my cube through script.

My script had a handful of problems with it, distinctly: calling '.scale' instead of '.dimensions'.

My working code looks like this: 

import bpy, csv

fp = "E:\Data_Viz_Prototype\Data Files\Workcenter_DPPM.csv"

obj = bpy.data.objects["Cube.002"]
cube = obj.data

with open( fp ) as csvfile:
    rdr = csv.reader ( csvfile)
    for i, row in enumerate (rdr):
        if i == 0: continue #Skip colum titles
        if row[2:3] != 2018: continue #Skip any rows not from 2018
        if row[3:2] != 1: continue #Skip any rows not from January
    wc, dept, year, month, run, rej, dppm = row[:]

if obj['Work_Center'] == '04-LSE200':
    obj.dimensions = (.5, .5, float(dppm))